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Managing the older person with diabetes in primary care

Diabetes is a very common condition in older people. The presence of other comorbidities, visual and manual dexterity problems, and their home circumstances can present the healthcare professional with challenges in the management of their diabetes ...

Jill Hill
RGN BSc(Hons)
Diabetes Nurse Consultant
Birmingham East and North PCT

Diabetes is a common long-term condition in which there is a chronically raised blood glucose level, caused by a complete or relative lack of insulin. There are two main types of diabetes: type 1 (previously known as insulin-dependent or juvenile-onset diabetes) and type 2 (previously known as noninsulin dependent or mature-onset diabetes.

Type 2 diabetes is more common than type 1 diabetes, and is a progressive condition.1 Initially, the body's tissues become less sensitive to the effects of insulin (insulin resistance). Losing weight, being more physically active and using insulin-sensitising agents such as metformin and the glitazones can all help to address this.

As the condition progresses, the beta cells gradually fail, leading to less insulin production; eventually, patients will need to supplement their own residual insulin supply with insulin injections. They continue to have type 2 diabetes, treated with insulin, and do not become type 1. The onset of type 2 diabetes is often insidious with few or no symptoms, so patients may have the condition for years before being diagnosed, and present with complications at diagnosis.2 Diabetes is diagnosed by the presence of symptoms including weight loss, thirst and polyuria (production of excess urine) and one abnormal venous blood glucose sample (7.0 mmol/L or higher if fasting or a random of 11.1 mmol/L or higher). In the absence of symptoms, two abnormal glucose readings are required to confirm diagnosis.3

Both types of diabetes can lead to the development of microvascular complications (retinopathy, nephropathy and neuropathy) and macrovascular complications, including cardiovascular disease, stroke and peripheral vascular disease. There is good evidence that for both type 1 and type 2 diabetes, the risk of complications can be significantly reduced by controlling risk factors (blood pressure, lipid and glycaemic).4,5

There is a National Service Framework for diabetes, which sets out 12 standards of care and also a number of National Institute for Health and Clinical Excellence (NICE) guidelines concerning the management of diabetes.6-9

Supporting older people with diabetes
Diabetes is more common in older people: up to 20% of those over the age of 80 years will have the condition.10 Often, these people may have a number of other comorbidities that will impact on their diabetes management and ability to self-care. They may also have had their diabetes a long time and be living with the consequences of many years of poor control. However, older people are just as varied as other groups of the population and while this article focuses on the particular issues for the elderly, readers may know of people in their 80s who require a multiple insulin injection regimen to allow them to live a flexible, active life.

Diagnosis
Diabetes may be easily missed in the older person. Symptoms can be vague and nonspecific, and may be put down to increasing age; for example, fatigue, urinary incontinence and changes in mental state such as depression, apathy, and confusion (Case study 1).

Case study 1
Mrs Bell is 79 years old and lives alone. She is finding it increasingly difficult to find the energy to go shopping and clean the house, despite drinking energy drinks. Her daughter notices her mother is always asleep in front of the television when she visits. Mrs Rogers asks her daughter to get her some pads when she next does her weekly shop, as she says her bladder is getting weak. She puts all these symptoms down to her age.

Repeated infections, a myocardial infarction or the presence of an ulcer that is not healing well may be the trigger for screening and identification of diabetes. Sometimes, diabetes is dramatically diagnosed when the patient develops hyperosmolar nonketotic state (HONK). The patient presents with very high blood glucose levels (30 mmol/L or greater), dehydration and the condition can sometimes cause coma. Ketones are not present in significant amounts. HONK has a high mortality rate as it usually occurs in elderly people who are less resistant to the effects of metabolic crisis and its treatment.

The aim for glycaemic control management for many older patients, particularly if they are frail and living alone, is the relief of hyperglycaemic symptoms but to avoid hypoglycaemia.

Targets will vary with individuals, circumstances and other existing conditions (eg, malignancy). The risk of developing diabetes complications needs to be weighed against the risk of falls from hypoglycaemia so strict glycaemic control may not be appropriate. This may cause conflict with practices chasing Quality and Outcomes Framework (QOF) points (Case study 2).

Case study 2
A GP has an 87-year-old patient on twice-daily Mixtard 30 (16 units in the morning and 10 units in the evening). The patient's HbA1c is 8.5%. He is considering increasing the dose to 20 units in the morning and 14 units in the evening.
This is an increase by almost a third in daily insulin dose! A 10% increase in dose is reasonable when adjusting insulin. However, choosing which insulin dose to adjust will need to be determined by blood glucose monitoring. If the blood glucose levels are above target during the day and into the evening, then the morning dose should be adjusted. If the prebedtime and prebreakfast readings are high, then the evening dose should be adjusted.
There should be a balance between predicted life expectancy and reduction of vascular risk against any improvement in diabetes control. For someone in their late 80s, avoidance of hyperglycaemic symptoms and hypoglycaemia would be appropriate, and 8.5% may represent a safe compromise.

Dietary advice may be of limited use but reducing the consumption of obvious sugars may be achieved (eg, changing from sugar in hot drinks to sweeteners). Some frail people may need supplementary feeds, which can result in hyperglycaemia. If these feeds are necessary, the glycaemic medication needs to be adjusted to compensate for this, even if it means initiating a simple insulin regimen.

There is limited research evidence for the effectiveness of oral antihyperglycaemic therapies in the very elderly as these people are usually excluded from trials by their age or existing complications and other co-morbidities. Metformin will be contraindicated in renal impairment, and sulphonylureas with a long duration of action (eg, glibenclamide) should be avoided, and others (eg, gliclazide) used with caution as their action time is prolonged in declining renal function, increasing the risk of hypoglycaemia.

Poor appetite and poor memory leading to missed meals, and loss of weight can also increase risk of hypoglycaemia in patients using sulphonylureas (and insulin). Episodes of hypoglycaemia may be misdiagnosed as cerebrovascular events or unusual behaviour (Case study 3).

Case study 3
Mr Rogers, aged 81 years, has had type 2 diabetes for 11 years. This is treated with glibenclamide 10 mg daily. His HbA1c is 6.1%. He visits a day centre twice a week for observation as he has had several falls recently. Today, lunch is later than usual. Staff notice Mr Rogers is disoriented and drowsy. What is the likely diagnosis and what has caused it?
It seems likely that Mr Rogers has hypoglycaemia. This can be confirmed by a capillary blood sample. Glibenclamide is a long-lasting sulphonylurea and if Mr Rogers' renal function is slowly deteriorating, the drug may not be eliminated within 24 hours. He has probably been on this treatment for many years and as his glycaemic control appears good (as judged by HbA1c of 6.1%), his treatment has not been changed. As his HbA1c is in the nondiabetic range, he may have been having periods of hypoglycaemia frequently but these have been missed (the cause of the falls?)

As type 2 diabetes is progressive, insulin will often be required to maintain reasonable glycaemic control. A choice of insulin regimens is available but, generally, simple regimens such as once-daily insulin with or without oral hypoglycaemic agents are recommended in the elderly. Those patients who have type 1 diabetes, however, will be unlikely to get reasonable glycaemic control with daily insulin. Active, motivated, older people who have flexible eating patterns and activity may prefer a basal bolus regimen where they can adjust the times and amounts of insulin they use depending on what and when they are eating.

A variable bolus regimen may be useful in people who need episodes of steroid therapy or who have an erratic eating pattern.

Some older people may have been injecting insulin for several years. Do check injection sites during their annual review: are they still suitable? (Arms and calves were recommended as injection sites years ago, but not now). Thighs may not be suitable if the patient has lost weight. Repeated injections into an area of skin can lead to lipohypertrophy, which are fatty or hard areas under the skin. The author remembers finding an "extra pair of knees" halfway up a 70 year-old patient's thighs, where she had injected exclusively for about 30 years!

A long-term insulin user may prefer to continue with using animal insulin. A selection of pork and beef insulin is still available from Wockhardt in cartridges to fit an Autopen device and vials for use with syringe. Changing from animal to human or analogue insulin needs to be undertaken with caution: anti-insulin antibodies develop over years in animal insulin users, particularly with beef insulin, which usually means they require a larger dose than a similar nonanimal insulin. If the dose is not reduced when changing, there is a risk of hypoglycaemia. Early symptoms of impending hypoglycaemia may be more marked when using animal insulin, so patients must be warned to react more quickly after changing to their new insulin.

Some insulin delivery devices may be particularly useful for those with poor eyesight or visual dexterity problems. The InnoLet device, produced by Novo Nordisk, looks like an egg timer and has a large dosing dial and is chunky to hold (Figure 1). The Optiset pen (Sanofi-aventis) can be preset by a carer for those with visual problems. Some patients may still be using syringes: there is no problem with this unless their eyesight has deteriorated and so conversion to a pen device may maintain independence. Most blood glucose meters tend to have large visual displays now but there is a "talking meter" available from BBI Healthcare for those with impaired sight.

Older people may have quite a fragile coping system for their daily lives. An elderly couple can support each other to compensate for difficulties in self-care (eg, drawing up insulin for the other) but if their partner dies or is hospitalised, the person's independence quickly crumbles. Being admitted to a residential home may not improve diabetes management.

The care of older people with diabetes living in residential homes can be a particular problem. The rapid turnover of staff, who are often young and poorly paid, means the development of skills vary considerably, even if staff are able to access appropriate training. Often, blood glucose monitoring is not available, making monitoring a challenge. Patients requiring insulin and not able to self-inject will require district nurse support. Patients may not get an annual diabetes review, especially if they are not mobile.11

Conclusion
Achievement of tight glycaemic control is not appropriate for older people, especially if they are frail. Avoid, or use with caution, oral agents that can cause hypoglycaemia. A simple once-daily insulin regimen is often sufficient to exclude symptoms of hyperglycaemia and minimise the risk of hypoglycaemia. This is also easier to manage if the patient requires district nurse support for injections. Older people vary in their circumstances and some have very active lifestyles and can benefit from a flexible insulin regimen.

References
1. Williams G, Pickup J. Handbook of Diabetes, 3rd edition. Oxford: Blackwell Publishing; 2004.
2. Davis TM, Stratton IM, Fox CJ, Holman RR, Turner RC. UK Prospective Diabetes Study 22. Effect of age at diagnosis on diabetic tissue damage during the first 6 years of NIDDM. Diabetes Care 1997;20:1435–41.
3. World Health Organization (WHO). Definition, Diagnosis and Classification of Diabetes Mellitus and its Complications. Geneva: WHO; 1999.
4. Diabetes Control and Complications Trial Research Group (DCCT). The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993;329:977-86.
5. UK Prospective Diabetes Study group (UKPDS). Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes. Lancet 1998;352:837-53.
6. Department of Health (DH). National Service Framework for Diabetes: Standards. London: DH; 2001. Available from: http://www.dh.gov.uk/en/Publicationsandstatistics/Publications/Publicati...
7. National Institute for Health and Clinical Excellence (NICE). Guidance on the use of patient-education models for diabetes: Technology Appraisal 60. London: NICE, 2003. Available from: http://www.nice.org.uk/nicemedia/pdf/60Patienteducationmodelsfullguidanc...
8. National Institute for Health and Clinical Excellence (NICE). Type 2 diabetes: Prevention and management of foot problems. London: NICE; 2004. Available from: http://www.nice.org.uk/nicemedia/pdf/CG010NICEguideline.pdf
9. National Institute for Health and Clinical Excellence (NICE). Type 2 diabetes: The management of type 2 diabetes. London: NICE; 2008.
10. Harris MI, Flegal KM, Cowie CC et al. Prevalence of diabetes, impaired fasting glucose, and impaired glucose tolerance in US adults. The Third National Health and Nutrition Examination Survey, 1988-1994. Diabetes Care 1998:21:518–24.
11. British Diabetes Association (BDA). Guidelines of Practice for Residents with Diabetes in Care Homes. London: BDA; 1999.